The literature of such catalysts and processes is quite extensive. Certain technical areas have been addressed as of particular interest as is readily apparent based on the large numbers of patents on certain technical topics, e.g., the use of certain zeolites in hydrocracking catalysts. Representative of the patents in this area are those relating to the use of ZSM-type zeolites in hydrocracking and include: U.S. Pat. No. 3,894,934 (ZSM-5); U.S. Pat. No. 3,871,993 (ZSM-5, ZSM-11, ZSM-12 and ZSM-21); U.S. Pat. No. 3,702,886 (ZSM-5); and U.S. Pat. No. 3,758,043 (ZSM-5 in combination with zeolite Y) of and U.S. Pat. No. 3,972,983 (ZSM-20).
Although the aforementioned patents on the use of ZSM-type zeolites in hydrocracking catalysts are of interest, the use of these zeolites has not been of significant commercial interest to date. The commercially significant activity in the hydrocracking area has been for the most part directed to further elaboration on the basic hydrocracking technology which has arisen in relation to zeolite Y, as disclosed in U.S. Pat. No. 3,130,007.
The development of hydrocracking catalysts based on a Y-type zeolite has taken many directions. Illustrative of the various processes which have arisen are those disclosed in the following patents:
U.S. Pat. No. 3,293,192 discloses a "synthetic ultra stable zeolitic aluminosilicate of the Y-type" (See U.S. Pat. No. 3,594,331, which discloses that Z-14HS is zeolite Y.) which has been prepared by calcining a low alkali metal Y zeolite and successively base exchanging the calcined product with a base solution containing ammonium or complex amino salts until the alkali content is less than 1 weight percent and then calcining this product.
Although there has been extensive development of Y-type hydrocracking catalysts there has been little development of truly new hydrocracking catalysts based on the development of new molecular sieve components. This paradox, the lack of new catalytic materials despite the sizable economic interest, is readily understood by an appreciation of the fact that the work horse of the commercial hydrocracking business is zeolite Y. As a result, the patent literature discloses the clear preference towards improving zeolite Y.
The existence of zeolite Y and its use as a catalyst for hydrocracking processes is now well accepted if not, in fact, legendary. Still, the state of the art relating to zeolite Y and its use in hydrocracking catalysts has been generally limited to ion-exchange techniques, aluminum extraction techniques, catalyst formulation techniques and to secondary treatment processes which tend to remove aluminum from zeolite Y.
The instant invention is distinguished from the hydrocracking catalysts and processes of the prior art by employing a novel family of non-zeolitic molecular sieves which can be employed in conjunction with the catalysts traditionally employed in hydrocracking processes. These novel non-zeolitic molecular sieves, when used in combination with traditional hydrocracking catalysts, are unique in their ability to provide products with product distributions different from those obtained by use of catalysts derived from zeolitic aluminosilicates alone.